11.10.2 SMTP Example

This example prompts the user for addresses needed in the message
envelope (`To' and `From' addresses), and the message to be
delivered. Note that the headers to be included with the message must
be included in the message as entered; this example doesn't do any
processing of the RFC 822 headers. In particular, the `To' and
`From' addresses must be included in the message headers explicitly.